EP 0520251 A3 19930421 - DISC-SHAPED MEMORY FOR BINARY INFORMATION
Title (en)
DISC-SHAPED MEMORY FOR BINARY INFORMATION
Publication
Application
Priority
DE 4121505 A 19910628
Abstract (en)
[origin: EP0520251A2] A disc-shaped memory of the CD type can be produced with relatively great production tolerances if the track scanned by the focused reading light beam comprises a continuous groove (3) having the following features - the width of the groove (3) is equal to or less than half the track width; - in the groove (3), first regions (3a) of relatively great depth (t1) and second regions (3b) of lesser depth (t2) follow on from one another with step-shaped transitions; - the lengths of the first regions and of the second regions embody the stored binary values; - the depth (t1) of the first regions (3a) is 1/4 of the wavelength of the reading light; - the depth (t2) of the second regions (3b) is about 1/16 of the wavelength of the reading light. <IMAGE>
IPC 1-7
IPC 8 full level
G11B 7/007 (2006.01); G11B 7/013 (2006.01); G11B 7/09 (2006.01)
CPC (source: EP)
G11B 7/0938 (2013.01); G11B 7/24079 (2013.01); G11B 7/24085 (2013.01)
Citation (search report)
- [A] EP 0100995 A2 19840222 - TOSHIBA KK [JP]
- [A] EP 0099085 A1 19840125 - TOKYO SHIBAURA ELECTRIC CO [JP]
- [AP] US 5115424 A 19920519 - NAKAJIMA HAJIME [JP], et al
- [A] EP 0173533 A2 19860305 - SHARP KK [JP]
- [A] GB 2091028 A 19820721 - PHILIPS NV
- [A] PATENT ABSTRACTS OF JAPAN vol. 7, no. 168 (P-212)(1313) 23. Juli 1983 & JP-A-58 73 026 ( NIPPON DENSHIN DENWA KOSHA )
Designated contracting state (EPC)
AT BE DE ES FR GB IT NL
DOCDB simple family (publication)
EP 0520251 A2 19921230; EP 0520251 A3 19930421; CS 201892 A3 19930113; DE 4121505 A1 19930107; HU 9201917 D0 19930830; HU T63509 A 19930830
DOCDB simple family (application)
EP 92109867 A 19920611; CS 201892 A 19920629; DE 4121505 A 19910628; HU 9201917 A 19920609